This invention relates to concrete form systems which are constructed from a series of end and side abutting panels such as sheets of plywood maintained in spaced relationship by tie members which extend between and through the plywood sheets and held on their outer ends by suitable hardware. The invention is concerned with providing improved extender devices which can be used to connect either standard or nonstandard size concrete forms one on top of the other to give the desired structural height.
It is particularly adaptable for use with those forms that are standardized with respect to their being made of wood with spaced reinforcement metal straps about 16 inches on center extending across each of the forms. Stacking is facilitated by the use of extender devices which reach between upper and lower metal reinforcement straps on the forms to hold them in their stacked positions.